Oscillators



Jan. 13, 1970 K. P. PALMER 3,489,176

OSCILLATORS Filed Nov. 21, 1967 FIGS ATTORNEYS United States Patent3,489,176 OSCILLATORS Kenneth Percival Palmer, Barford, near Warwick,England, assignor to Joseph Lucas (Industries) Limited,

Birmingham, England, a British company Filed Nov. 21, 1967, Ser. No.684,822 Int. Cl. F15b /00; G05b 19/44; G05d 16/00 US. Cl. 137624.14 4Claims ABSTRACT OF THE DISCLOSURE An oscillator comprising a membermounted upon a spring for oscillation, there being at least one inputsupplied in use, with impulses, at least one further passage receivingimpulses from the associated input to cause oscillation of the member,and at least one output passage receiving impulses from the associatedinput, the frequency of the impulses in the output passage being equalto those of the input when the member is oscillating at the naturalfrequency of the spring.

This invention relates to oscillators which are intended to be actuatedby supply of fluid under pressure and the object is to provide such anoscillator in a convenient form.

In accordance with the present invention an oscillator comprises aninput passage intended to communicate with a source of fluid atsubstantially steady pressure, a member carried by a spring and arrangedto oscillate under the control of the spring, an input nozzle arrangedto communicate with the input passage and disposed adjacent to themember and spring assembly, the arrangement being such that flow offluid through the input nozzle creates reaction forces tending tooscillate the member and spring assembly at a frequency related to thenatural resonance frequency of the assembly and as the member and springoscillate, the member controls the flow of fluid to the output passageat the same or a multiple of the frequency.

The invention will now be described by way of ex ample with reference tothe accompanying drawings in which:

FIGURE 1 is a diagrammatic representation of an oscillator constructedin accordance with the invention, and

FIGURES 2, 3 and 4 are alternative forms of oscillators.

The oscillators are intended for use in installations in corporating asource of fluid at steady or substantially steady pressure, and a signalreceiving device. The installation is intended to provide, in theexamples shown, an output signal to said device in the form of a seriesof fluid pressure impulses.

Referring to FIGURE 1 the oscillator comprises an input passageconnected, in use, to the steady pressure source (not shown), thispassage 10 communicating through a pair of restrictors 11, 12 With apair of input nozzles 13, 14 respectively. Arranged adjacent to theinput nozzles 13, 14 are a pair of knives 15, 16 respectively, thesebeing carried by a member 17, which is mounted upon a substantiallystraight blade-like cantilever spring 18, fixed at one end and upon theother end of which the member 17 is mounted. The arrangement is suchthat oscillation of the member 17 and spring 18 under the control of thespring results in intermittent interruption of the flow of fluid out ofthe input nozzles 13, 14 by means of the knives 15, 16 respectively.

Communicating with the passages leading to the nozzles 13, 14 anddownstream of the restrictors 11, 12 respectively are a further pair ofpassages 19, 20 respective- 3,489,176 Patented Jan. 13, 1970 1yterminating in nozzles 21, 22. These are disposed at opposite sides ofthe cantilever spring 18 respectively.

The input nozzles 13, 14 are, in the rest position of the member 17 andthe knives 15, 16 arranged so that, as shown, the nozzle 13 is closedwhilst the other nozzle 14 is, at least partly open.

Communicating with the passages 19, 20 are respective outlet passages23, 24, leading to the device, or devices for receiving the outputsignals.

In use, steady pressure is applied through the input passage 10 andreaches the nozzles 13, 14. The nozzle 13 however is closed, 'so that abuild up of pressure occurs in the associated passage 19 resulting in ajet of fluid being discharged through the nozzle 21 against one side ofthe cantilever spring 18, causing the spring 18 and the member 17 to bedeflected to a position in which the nozzle 14 is closed by its knife16. This will open the passage 13 causing the pressure in the passage 19to decay and at the same time pressure will build up in the passage 20to cause discharge through the nozzle 22 to deflect the member 17 andthe cantilever spring 18 in the opposite direction.

The member 17 and cantilever spring 18 must oscillate at their naturalfrequency. Each time pressure builds up in the passages 19 or 20, therewill be a pressure build up in the associated output passages 23 or 24respectively. The frequency of the output nozzles in these outputpassages will be equal to the spring and member natural resonancefrequency.

Referring to the construction in FIGURE 2, the member 17 carries a pairof knives 15, 16, which are insertable between pairs of opposed nozzles25, 26 and 27, 28 respectively, and the fluid received in the receivingnozzles 26, 28 is transmitted through passages 29, 30 to nozzles 31, 32disposed at opposite sides of the cantilever spring 18 respectively. Themode of operation of this device is similar to that of the constructionillustrated in FIGURE 1, the nozzles 25, 26 and 27, 28 beingnon-symmetrical with respect to the rest positions of the knives 15, 16so that oscillation of the member 17 and the spring 18 can begin fromthe rest position.

Referring to FIGURE 3 a simplified form of the oscillator has adeflector plate 33 carried at an inclined angle by the member 17, andthis is arranged adjacent to an input nozzle 34 disposed at the end ofthe input passage 10, the deflector 33 being deflected by the action offluid pressure from the input nozzle 34. The magnitude of theoscillators is such that the deflector plate 33 moves out of alignmentwith the nozzle 34 at either end of the stroke so that the spring 18tends to return to its rest position at which it again receives adeflecting force, thus generating the oscillatory movements. The member17 also carries a knife 35 adjacent to which is a nozzle 36communicating with a restricted passage 37. Connected to this passage 36between the restrictor and the nozzle 36 is an output passage. Thepassage 37 is, in use, supplied with fluid at a steady pressure and theoscillation of the member 17 will alternatively permit build up anddecay of pressure in the output passage 38. In this construction, thedeflector plate 33 is shaped to minimise changes in pressures in theinput nozzle 34 resulting from proximity of the plate 33 to the nozzle34.

In the further form of oscillator shown in FIGURE 4 there is an L-shapedpassage 39 in the member 17, one limb of which extends substantially inthe direction of the length of the spring 18 and is at rest disposedsubstantially in alignment with an input nozzle formed at the end of theinput passage 10, and the other limb of the L-shaped passage 39terminating in the side face of the member 17 and being arranged todischarge a jet of fluid when registration with the inlet nozzle occurs,thus causing a reaction force tending to deflect the member and spring.An output signal is obtained in the manner described in relation to theFIGURE 3 construction, similar parts being designated by like numerals.Other arrangements for producing output signals can be used in oneexample the fluid emitted from the outlet of the passage 39 in theFIGURE 4 construction can be utilised to control an output signal. Thefrequency of the output, in this instance will be twice the resonancefrequency of the spring and member.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. An oscillator comprising an input passage intended to communicatewith a source of fluid at substantially steady pressure, a membercarried by a spring and arranged to oscillate under the control of thespring, a knife carried by the member, an input nozzle communicatingwith the input passage and disposed adjacent to the member and springassembly, the position of the knife controlling flow of fluid throughthe input nozzle, a further passage terminating in a nozzle arranged todischarge fluid under pressure from the input passage in a direction tocause oscillation of the spring and member, an output passagecommunicating with said further passage, the member and knife beingdisposed to occupy a first position in which flow to the further passageand to the output passage can take place, and a second position in whichsuch flow ceases to occur.

2. An oscillator as claimed in claim 1 in which two input nozzlescommunicate with the input passage, the member has two knives to controlfluid flow through the input nozzles respectively, and two of saidfurther passages, terminating in respective nozzles, are arranged to '4discharge fluid in opposite directions to cause oscillation of thespring and member, and two output passages communicate with the furtherpassages respectively.

3. An oscillator as claimed in claim 1 in which the further passagecommunicates directly with the inlet passage and the knife is arranged,in its second position, to cut off or restrict flow through the inputnozzle, the flow instead occurring through the further passage and alsothrough the output passage, theknife', in its first position, permittingflow through the input nozzle so that flow through the further passageand the output passage ceases to occur.

4. An oscillator as claimed in claim 1 in which a fur ther nozzle isdisposed at the end of the further passage, said further nozzle beingdisposed opposite to the input nozzle, the knife being arranged in itssecond position, to interrupt fluid flow between the input nozzle andthe further nozzle of the further passage, but when the knife is in itsfirst position, flow in the further passage is permitted and floW willalso occur in the output passage.

References Cited UNITED STATES PATENTS 3,260,456 7/1966 Boothe 137-81.5X 3,275,015 9/1966 Meier 13781.5 3,292,648 12/1966 Colston 137-81.5 X3,323,721 6/1967 Topfer 235-201 ALAN COHAN, Primary Examiner US. Cl.X.Ri 13785

